Alexander george strathern



A. G. STRATHERN. SCREW CLAMP 0R GRIPPING DEVICE.

APPLICATION FILED DEC. 20, I918;

Patented Nov. 18, 1919.

ALEXANDER GEORGE STRATHERN, 0F GLASGOW, SCOTLAND.

SCREW CLAMP OR GRIPPING DEVICE.

Specification of Letters Patent.

Patented Nov. 18, 1919.

Application filed December 20, 1918. Serial No. 267,655.

To all whom it may concern:

Be it known that I, ALEXANDER GEORGE STRATHERN, a subject of the King ofGreat Britain and Ireland, residing at 50 Wellington street, in the cityand county of Glasgow, Scotland, have invented certain new and usefulImprovements in Screw Clamps or Gripping Devices, of which the followingis a specification.

This invention relates to screw clamps or gripping devices-sometimescalled grabsof the type comprising two arms hinged or pivotedtogether-like the two parts of tongs or pincers or scissorsa grippingmember being provided on the one end of each arm, and a rod, oppositelythreaded at its two ends, being arranged to engage with the two arms sothat, by rotating this rod in the one direction, the two grippingmembers will be forced toward each otherand can thus grip an object orhold two or more objects togetherand, by rotating the rod in the otherdirection, the two gripping members will be forced apartand will thusrelease an object or objects held.

The object of the present invention is to provide an improved clamp ofthis type which will be specially suitable for engaging with a bodyhaving two faces nearly but not quite parallel, e. g. the flanges of arolled steel joint of I-shaped or similar cross section.

The present invention consists in a clamp of this type characterizedwiththe above object in viewby a special construction (which will behereinafter more fully described) involving the formation of the armseach of two flat parallel bars.

The invention is illustrated by the accompanying drawing in which Figure1 is an elevation of the clamp, and

Fig. 2 is a plan thereof.

Referring to the drawing, the arms of the clamp are built up of flatparallel bars A, A and B, B respectively. At one end of the one arm andthe corresponding end of the other arm are arranged gripping members orjaws D, D which lie between the two bars of the arms and aretransversely pivoted thereto. At the other end of each arm is arranged anut, E or E which lies between the two bars of the arm and is alsopivoted transversely thereto. The nuts are tapped right and left handrespectively and receive the two ends of the operating rod or doubleended screw F which is threaded right and left hand at its two ends toengage with the nuts in the manner of a turn buckle. The two arms arehinged together by the pivot C which is arranged intermediate betweenthe gripping members D, D and the nuts E, E The axes of the hinge pivotC and of the pivots of the members D, D are perpendicular to the planesof the bars A, A B, B

The rod F is provided with means for rotating it by a spanner or thelike. It may for example be formed with an enlarged socketed orapertured portion of squared section as shown at G.

The construction as above described allows of the production of a clampwhich combines effectiveness in action with moderate cost, handiness,strength, durability, and relative lightness.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is 1. A screw clamp of the type hereinbefore mentioned,characterized by the arms being formed each of two fiat parallel bars,gripping members placed between and pivoted transversely to the two barsof their respective arms at one end thereof a nut being placed between,and pivoted transversely to the two bars of each arm at the other endthereof, and threaded operating rod engaging said nuts, the two armsbeing hinged together at an intermediate point, and the axes of thehinge and pivots being perpendicular to the planes of the arm bars,substantially as described and illustrated.

2. A screw clamp comprising arms pivotally connected with each otherintermediate their ends and disposed in crossed relation in X-shapedformation and providing substantially parallel forward ends, relativelylong intermediate crossed portions angularly disposed with relation tothe forward ends to space said forward ends a substanthe said nuts andprovided with a griptial distance apart, and relatively short rear pingportion for turning said screw rod. 10 ends substantially parallel andspaced at a In testimony whereof I afiix my signasubstantial distanceapart, oppositely disture in presenceof two witnesses.

posed gripping ne nbers pivoted onthe for- ALEXANDER'GEORGE STRATHERN.ward ends oppositely disposed nuts piv- WVitnesses: oted on the rearends, and a screw rod hav- E. L. CRE

ing right and left hand threads screwing-in" A, 'E." VIDALC

